CN102692666A

CN102692666A - Manufacture method of polarizing plate

Info

Publication number: CN102692666A
Application number: CN201210078056XA
Authority: CN
Inventors: 高畑弘明; 古川淳; 广岩梓; 清水英满
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2011-03-25
Filing date: 2012-03-22
Publication date: 2012-09-26
Anticipated expiration: 2032-03-22
Also published as: JP5756313B2; CN102692666B; TWI535571B; KR101879875B1; JP2012203205A; TW201247418A; KR20120110021A

Abstract

The invention relates to the manufacture method of a polarizing plate (4), comprising the procedures from (A) to (D). (A) an optical film (2) is coated by adhesive by a coating machine with a control portion possessing the coating thickness of adhesive; (B) the thickness of the coated film is measured by two spectral interferometric thickness gauges (14, 15), the thickness of the coated adhesive is obtained by thickness difference; (C) an overlapped spectral film (1) presses the optical film (2) through holding rollers (20, 21), and the spectral film (1) and the optical film (2) are connected by adhesive; and (D) control is provided based on the measured thickness X of the adhesive and a preset thickness Y.

Description

The manufacturing approach of polarization plates

Technical field

The present invention relates to manufacturing approach as the polarization plates of liquid crystal display member use.

Background technology

Form the liquid crystal panel of the core of liquid crystal indicator, constitute in the two sides of liquid crystal cells configuration polarization plates usually.Usually polarization plates is for being fitted with the structure that the diaphragm of transparent resin system forms at a face of the light polarizing film of polyvinyl alcohol resin system by tackifier.In most cases on another face of light polarizing film, be fitted with transparent resin film by tackifier; The transparent resin film of this side and the diaphragm of opposition side are same; Except being the film that only has the defencive function of light polarizing film; Except defencive function, also optical compensation, the viewing angle compensation with liquid crystal cells is purpose, also is to have given in the face and/or the so-called phase retardation film of the phase differential of thickness direction.In this instructions, the diaphragm that will fit in such light polarizing film by tackifier, phase retardation film etc. are called " blooming ".Blooming is generally liquid tackifier to the used tackifier of the applying of light polarizing film, through the curing reaction of this liquid adhesive, between light polarizing film and blooming, shows bonding force.

In recent years, be that the price of the liquid crystal indicator of representative descends rapidly with the TV, to constituting this member strong request low price, on the other hand, the requirement of quality is also become stronger.In this trend; Be used to make the tackifier of polarization plates; Also just be defined to the water system tackifier of specific resin such as cellulose-based resin, changing to the more active energy ray curable tackifier of kind of the blooming that can use from the kind of the blooming that can use.Used the light polarizing film of active energy ray curable tackifier and the applying of blooming, for example in TOHKEMY 2004-245925 communique, proposed.

Prepare liquid active energy ray curable tackifier; Use is coated with machine or is being formed on the groove on surface and support liquid adhesive and it is transferred to the gravure roll (gravure roll) that is applied the thing surface being applied on the thing the direct mould of this liquid adhesive of coating, on the binding face of light polarizing film, carries out pre-coated at blooming.In addition, in the overlapping light polarizing film of this adhesive applicating face, irradiation ultraviolet radiation, electron ray isoreactivity energy-ray make adhesive solidification, show bonding force thus.About using the mode of such active energy ray curable tackifier, the blooming that can use is many, is unusual effective method.

Manufacturing approach as the polarization plates of using this active energy ray curable tackifier; For example in TOHKEMY 2009-134190 communique, disclose and obtain duplexer by tackifier overlapping protection film respectively on the two sides of light polarizing film; Form this duplexer of outside surface driving fit of the convex surface of Yen arcuation at throughput direction, the method for shining active energy beam simultaneously along this duplexer.According to this method, can make and to be suppressed at the incidental contrary curling polarization plates that waveform curls and has superperformance that reaches of the polarization plates that obtains.

In the method for the document, think the thickness of the adhesive layer that on diaphragm, forms, because the polarization plates of manufacturing contrary curled and waveform curls and do not have bigger influence, so there is not too big necessity that the applied thickness of tackifier is managed.Yet though be most to be through the thickness fluctuation of adhesive layer no problem level to produce defectives such as bubble sometimes, under the big situation of this defective, the yield rate of polarization plates can reduce sometimes.And then; When stable manufacturing cheapness and more high performance polarization plates; In most cases the active energy ray curable adhesive applicating must be thicker than water system tackifier in the past; In addition, owing to himself costliness, also expect the thin-walled property of polarization plates self, hope to manage according to mode for the thickness of considering the necessary minimum after the fluctuating range (variation).

As with online mode, promptly behind the coating binder in the manufacturing line of polarization plates, before the applying of light polarizing film and blooming, the machine of applied thickness being measured in order to manage, known have an infrared ray film thickness gauge.But the infrared ray film thickness gauge has restriction on resolution characteristic, so the thickness with the overlay (adhesive layer) of counting the formation of μ m degree is accurately measured in such on the film of carrying continuously, being difficult to of kine bias vibration plate manufacturing line.When explaining particularly, in the polarization plates manufacturing line, as after state shown in Figure 1, light polarizing film and the blooming of fitting at its at least one face do not have each other supporting mass separately and are carried continuously, and fit somewhere.In the film of carrying so continuously; Delicate shaking (vibration) takes place in thickness direction and the direction (flow direction) that applies tension force; Have under such state that shakes; When wanting to utilize the infrared ray film thickness gauge that the thickness of overlay is measured, can only obtain ± precision about 1 μ m, it in fact is being impossible applied thickness being managed as the basis with it.In addition; When wanting the thickness of the adhesive layer that on blooming, forms to be measured with the infrared ray film thickness gauge; Although must there be the restriction of obvious difference at the infrared ray absorbing peak that the infrared ray absorbing peak and the tackifier that exist so-called blooming to provide are provided; But according to the kind of blooming and both summits are overlapping, also can't obtain measured value self sometimes.Therefore so far in the manufacturing of the polarization plates of having used liquid adhesive, still can not carry out the thickness of the liquid adhesive that On line inspection is coated with on film.

Summary of the invention

Therefore; Problem of the present invention is; Be provided on the light polarizing film when with the active energy ray curable tackifier being the liquid adhesive applying blooming of typical example; Through the applied thickness of online management tackifier, make the fluctuation minimizing of its thickness and suppress the generation of defects such as bubble in the adhesive layer, can make the method for polarization plates simultaneously at an easy rate.

The inventor etc. study intensively in order to solve above-mentioned problem, and the result finds, with the adhesive applicating of liquid state on blooming; And make this overlay fit in light polarizing film when making polarization plates, through measure the thickness of the tackifier after applying with specific method, accurately obtain this thickness; Based on its result; The coating thickness of the tackifier when control applies can be made the polarization plates that thickness is even and defective is few of tackifier thus, so that has accomplished the present invention.

That is, the present invention provides the manufacturing approach of following polarization plates, and it is for making the method for polarization plates by tackifier at the blooming of the light polarizing film applying thermoplastic resin system of polyvinyl alcohol resin system, possesses following (A), (B), (C) and (D) each operation.

Working procedure of coating (A): use the coating machine of coating thickness control gear, at the above-mentioned tackifier of coating on the binding face of light polarizing film of blooming with tackifier;

Measure operation (B): utilize the spectral interference method of beam split wavelength region may in surpassing the scope of 800nm; Before working procedure of coating, measure the thickness of blooming; The gross thickness of the tackifier after measuring blooming and coating behind the working procedure of coating is simultaneously obtained the thickness of the tackifier after the coating with online mode by the absolute value of the difference of these measured values;

Bonding process (C): coating and passed through overlapping light polarizing film and pressurization on the adhesive faec of said determination operation in above-mentioned working procedure of coating; And

Control operation (D): be based on the mensuration thickness X of setting thickness Y with the tackifier that in measuring operation, obtains of the tackifier of setting in the scope of 0.5～5 μ m, the coating thickness control gear of tackifier is controlled.

The manufacturing approach of polarization plates of the present invention preferably possesses following (D) operation.

Control operation (D): when the absolute value of the difference of the above-mentioned Y of mensuration thickness X of the tackifier that obtains in the said determination operation is that setting is when above with respect to the ratio of the setting thickness Y of the tackifier of in the scope of 0.5～5 μ m, setting; For example be 5% when above, above-mentioned coating thickness control gear is controlled.

In addition, the otherwise method of the present invention provide possess following (A), (B), (C) and (D) manufacturing approach of the polarization plates of each operation.

(A) use coating machine coating binder on the blooming of thermoplastic resin system of the control part of coating thickness, obtain the operation of duplexer with tackifier;

(B) utilization is set in the beam split wavelength region may above the spectral interference method in the scope of 800nm; Measure the optical thickness of the blooming before the coating binder and the optical thickness of the blooming behind the coating binder, and obtain the operation of the thickness of the tackifier after the coating based on the difference of the optical thickness of the blooming before the coating binder and the optical thickness behind the coating binder;

(C) light polarizing film of overlapping polyvinyl alcohol resin system on through the tackifier coated face of the blooming measured is pressurizeed to blooming with respect to light polarizing film, the bonding process that light polarizing film and blooming is fitted by tackifier; And

(D) be based on the thickness X that the quilt of setting thickness Y and the tackifier of the tackifier of setting in the scope of 0.5～5 μ m is obtained, the operation that control part is controlled.

The method of other aspects of the present invention preferably possesses the operation of following (D).

(D) when the absolute value of the difference of the setting thickness Y of thickness X that the quilt of above-mentioned tackifier is obtained and tackifier be that setting is when above with respect to the ratio of the setting thickness Y of the tackifier of in the scope of 0.5～5 μ m, setting; For example be 5% when above, the operation that control part is controlled.

According to the present invention; When on light polarizing film, during by tackifier applying blooming, using the film thickness gauge of regulation, measure the film thickness before and after the working procedure of coating; The thickness of the tackifier that on blooming, forms with the online mode instantaneous measurement thus; Its result is sent to the mechanism of the coating thickness of the control tackifier that coating machine has,, therefore can makes the uniform polarization plates of thickness of tackifier so that control this coating thickness.Its result can suppress to result from the uneven thickness of tackifier and the defectives such as bubble that are easy to generate.

Description of drawings

The configuration routine summary side elevation of Fig. 1 for representing the manufacturing installation that the present invention preferably uses.

Fig. 2 is the block diagram of an example of the relation between expression each operation of the present invention.

The summary side elevation of the configuration of the manufacturing installation that Fig. 3 uses among the embodiment for expression.

Among the figure: 1-light polarizing film, 2-first blooming, 3-second blooming, 4-polarization plates; 10-first coating machine, 11-gravure roll, 12-second coating machine, 13-gravure roll; The 14-first spectral interference formula film thickness gauge, the 15-second spectral interference formula film thickness gauge, 16-the 3rd spectral interference formula film thickness gauge, 17-the 4th spectral interference formula film thickness gauge; 18-active energy beam (ultraviolet ray) irradiation unit, 20,21-fits and to use niproll, 22,23-coiling front nip rollers; The 24-deflector roll, take up roll, 30-take up roll are used in the 26-irradiation.

Embodiment

Among the present invention,, make polarization plates by the blooming of tackifier applying thermoplastic resin system on the light polarizing film of polyvinyl alcohol resin system.Blooming can only be fitted in the single face of light polarizing film, also can be fitted in the two sides of light polarizing film.Under the situation of the two sides of light polarizing film applying blooming, the applying of the blooming of one side can be used method of the present invention, and the applying of the blooming on two sides also can be used method of the present invention.

[light polarizing film]

Light polarizing film is a polyvinyl alcohol resin system; It is the film with following character: in inciding the light of this film; Transmission has the light of the vibration plane of certain direction; The light of absorbed oscillation face and its quadrature is typically, and is adsorbed with the dichromatism pigment on the polyvinyl alcohol resin and this dichromatism pigment is orientated.Constituting the polyvinyl alcohol resin of light polarizing film, is that resin carries out saponification and obtains through making polyvinyl acetate.Polyvinyl acetate as the polyvinyl alcohol resin raw material is a resin, except polyvinyl acetate as the homopolymer of vinyl acetate, can also be vinyl acetate with can with the multipolymer of other monomers of its copolymerization.Can through the film of said polyvinyl alcohol resin system implemented uniaxial tension, utilize dyeing that the dichromatism pigment carries out, and dyeing after the boric acid crosslinking Treatment, make light polarizing film.As the dichromatism pigment, can use iodine, dichromatic organic dyestuff.Uniaxial tension can be implemented before the dyeing that utilizes the dichromatism pigment, also can implement simultaneously with the dyeing that utilizes the dichromatism pigment, can also be after the dyeing that utilizes the dichromatism pigment, implement in the for example boric acid crosslinking Treatment.So make and be adsorbed with the light polarizing film of the polyvinyl alcohol resin system that dichromatism pigment and dichromatism pigment be orientated, become one of raw material of polarization plates.

[blooming]

The blooming of applying thermoplastic resin system is made polarization plates on this light polarizing film.Blooming preferably is in 1.4～1.7 scope in 20 ℃ of refractive indexes of measuring through the D line of temperature.The refractive index of blooming is measured based on JIS K 0062:1992 " the detecting refractive index method of chemicals ".If blooming has the refractive index of this scope, the display characteristic when then the polarization plates of manufacturing being assembled into liquid crystal panel is excellent.For the same reason, the preferred index of blooming is 1.45～1.67 scope.Because the contrast of the polarization plates that obtains is improved, especially when being assembled into liquid crystal panel for black the demonstration, the possibility that produces degradation undesirable condition under the brightness reduces, so preferred its haze value of this blooming is in the scope about 0.001～3%.Haze value is with the value that (diffused transmission rate/full light transmittance) * 100 (%) define, and measures based on JIS K 7136:2000 " mist degree of plastics-transparent material ask calculation method ".

As the thermoplastic resin that constitutes such blooming, for example can enumerate following resin,, will utilize refractive index that the D line measures as n here 20 ℃ of temperature _D(20 ℃) illustrate in the lump.

Cyclic olefine resin (n _D(20 ℃)=about 1.51～1.54),

Crystalline polyolefin is resin (n _D(20 ℃)=about 1.46～1.50),

Polyester based resin (n _D(20 ℃)=about 1.57～1.66),

Polycarbonate-based resin (n _D(20 ℃)=about 1.57～1.59),

Acrylic resin (n _D(20 ℃)=about 1.49～1.51),

Tri acetyl cellulose is resin (n _D(20 ℃)=about 1.48) etc.

The cyclic olefine resin is to be the polymkeric substance of main composition unit with the cyclic olefine monomer like ENB and so on; Comprise the resin that the ring-opening polymerization polymer hydrogenation that makes the cyclic olefine monomer obtains, also comprise the cyclic olefine monomer, with like the chain ethylene series monomer of the carbon number 2～10 of ethene, propylene and so on and/or like the addition polymer of the aromatic vinyl monomer of styrene and so on etc.

Crystalline polyolefin is that resin is that chain ethylene series monomer with carbon number 2～10 is the polymkeric substance of main composition unit, comprises the above multipolymer of the homopolymer of chain ethylene series monomer, the binary of having used the chain ethylene series monomer more than 2 kinds or ternary.Particularly, comprise the homopolymer of polyethylene-based resin, polypropylene-based resin, ethylene-propylene copolymer, 4-methyl-1-pentene or the multipolymer of 4-methyl-1-pentene and ethene or propylene etc.

About polyester based resin, except aromatic polyester resin, also comprise aliphatic polyester based resin like polyethylene terephthalate, PEN and so on.Polycarbonate-based resin is typically that reaction through the bisphenol-A photoreactive gas obtains and has the polymkeric substance of carbonic acid ester bond-O-CO-O-at main chain.Acrylic resin typically is to be the polymkeric substance of main composition unit with the methyl methacrylate, except the homopolymer of methyl methacrylate, also comprises the multipolymer of methyl methacrylate and other methacrylate and/or acrylic ester etc.Tri acetyl cellulose is that resin is cellulosic acetic acid esters.

Utilize solvent cast method, extrusion by melting etc. to process film, can process the blooming that uses in this embodiment by these thermoplastic resins.In addition, also can be with further processing the blooming that uses in this embodiment behind the system film through single shaft or biaxial stretch-formed film.Blooming also can be implemented easy the to be bonding processing like saponification processing, corona treatment, plasma treatment, primary coat processing or anchoring coated and so on to its binding face before fitting in light polarizing film.In addition, also the various processing layers like hard conating, anti-reflection layer or antiglare layer and so on can be set on the face of blooming and binding face opposition side light polarizing film.

Blooming preferably has the thickness about 5～200 μ m usually.When optics is lepthymenia, lack operability, in the polarization plates manufacturing line, rupture or the possibility of bringing out the fold generation uprises.On the other hand, when blocked up, the polarization plates thickening that obtains, weight also becomes greatly, therefore makes commodity impaired sometimes.From these reasons, more preferably thickness is 10～120 μ m, further preferred 10～85 μ m.

[tackifier]

On aforesaid light polarizing film during the applying blooming, at first, at the binding face coating binder to light polarizing film of blooming.About the thickness of tackifier, be that the scope at 0.5～5 μ m is set at setting.When its thickness is lower than 0.5 μ m, aspect bonding strength, produce uneven sometimes.On the other hand, when its thickness surpassed 5 μ m, not only manufacturing cost increased, and also can the form and aspect of polarization plates be exerted an influence sometimes according to the kind of tackifier.If thicker in this scope, for example would be more than the 3.5 μ m, especially more than the 4 μ m.Change even if its thickness has a little, also be difficult to occur because of the defectives such as bubble due to it, but on the other hand, it is very possible relevant with the increase of cost so to thicken thickness, so hopes attenuate within the bounds of possibility.From these reasons, the preferred thickness of tackifier is 1～4 μ m, further is preferably the scope of 1.5～3.5 μ m.

About tackifier; So long as under the state that is coated with of liquid state, supply with; Can use the various tackifier that all the time are used to make polarization plates; But from viewpoints such as against weather, polymerisms, preferably contain the compound, for example epoxy compound of cationically polymerizable, more specifically like the epoxy compound that in molecule, does not have aromatic rings of TOHKEMY 2004-245925 communique record active energy ray curable tackifier as one of active energy ray-curable composition.Such epoxy compound can for: be that the raw material of the aromatic epoxy compound of typical example is that aromatic polyhydroxy compounds carries out nuclear hydrogenation for example, and make its glycidyl ether and the hydrogenation epoxy compound that obtains diglycidyl ether with bisphenol-A; Has at least 1 alicyclic epoxy compound that is bonded to the epoxy radicals of aliphatics ring in the molecule; Glycidol ether with aliphatic polyhydroxy compound is aliphatic epoxy compound of typical example etc.In addition; In the active energy ray curable tackifier; Except being the cationically polymerizable compound of typical example with the epoxy compound; Usually can also cooperate polymerization initiator, especially cooperate irradiation through active energy beam to produce the light cationic polymerization initiators that kation kind or lewis acid are used to cause the polymerization of cationically polymerizable compound.And then, cooperate through heating make that polymerization causes hot cationic polymerization initiators, in addition, can also cooperate various adjuvants such as photosensitizer.

Under the situation of applying blooming on the two sides of light polarizing film, the tackifier that is applied to each blooming can be the same or different, and from productive viewpoint, under the prerequisite of the bonding force that obtains appropriateness, preferred two sides is identical tackifier.

[manufacturing approach of polarization plates]

In this embodiment,, make polarization plates by the light polarizing film applying blooming of tackifier in the polyvinyl alcohol resin system of above explanation.At this moment, through following (A), (B), (C) and each operation (D).

(A) use the coating machine of coating thickness control gear, at the working procedure of coating to the binding face coating binder of light polarizing film of blooming with tackifier;

(B) through the beam split wavelength region may being set in above the spectral interference method in the scope of 800nm; Before working procedure of coating, measure the thickness of blooming; The gross thickness of the tackifier after measuring blooming and coating behind the working procedure of coating simultaneously is by the online Determination of thickness operation of obtaining the tackifier after the coating of their absolute value of difference of measured value;

(C) in above-mentioned working procedure of coating, be coated with and pass through on the adhesive faec of said determination operation, the bonding process of overlapping light polarizing film and pressurization; And

(D) when the absolute value of the difference of the mensuration thickness X of the tackifier that obtains in the said determination operation and above-mentioned Y be setting when above with respect to the ratio of the setting thickness Y of the tackifier of in the scope of 0.5～5 μ m, setting, the control operation that above-mentioned coating thickness control gear is controlled.

Fig. 1 is the side view that schematically shows the configuration example of the manufacturing installation that the present invention preferably uses, and Fig. 2 is the block diagram of an example of the relation of expression each inter process of the present invention.Below, scheme with reference to these on the limit, and the limit is elaborated to the manufacturing approach of polarization plates.

About the manufacturing installation shown in Fig. 1, constitute as follows: light polarizing film 1 is carried on the limit continuously, limit first blooming 2 of on one face, fitting, and second blooming 3 of on one side in addition, fitting, manufacturing polarization plates 4, and be wound up on the take up roll 30.As shown in the drawing, be typically on the two sides of light polarizing film 1 and be fitted with blooming respectively, but only be also contained in this embodiment certainly in the mode of a face applying blooming of light polarizing film 1.For the mode of this situation, from following explanation, omitted the explanation of relevant another blooming, so long as those skilled in the art just can easily understand enforceable degree.

About first blooming 2; At first; Utilize the first spectral interference formula film thickness gauge 14 to measure its thickness; Then by first coating machine 10 after fitting in the face coating binder of light polarizing film 1, utilize the second spectral interference formula film thickness gauge 15 to measure the gross thickness of the tackifier after bloomings and the coating, by the thickness of obtaining the tackifier after the coating based on the absolute value of the difference of the measured value of 2 spectral interference formula film thickness gauges 14,15.Equally; About second blooming 3; At first, utilize the 3rd spectral interference formula film thickness gauge 16 to measure its thickness, follow by second coating machine 12 after fitting in the face coating binder of light polarizing film 1; Utilize the 4th spectral interference formula film thickness gauge 17 to measure the gross thickness of the tackifier after bloomings and the coating, by the thickness of obtaining the tackifier after the coating based on the absolute value of the difference of the measured value of 2 spectral interference formula

film thickness gauges

16,17.

Measure thickness first blooming 2 and second blooming 3 afterwards of adhesive applicating front and back; Tackifier coated face is separately overlapped on the two sides of light polarizing film 1; Carry out clamping and on thickness direction, pressurize with

niproll

20,21 to fit, receive irradiation then from the active energy beam of active energy beam irradiation unit 18, make adhesive solidification after; Through coiling

front nip rollers

22,23, the polarization plates 4 that obtains is wound up on the take up roll 30.

In first coating machine 10 and second coating machine 12, utilize gravure roll 11,13 coating binder on first and second blooming 2,3 that is provided with separately.Face of light polarizing film 1 or first blooming 2 and second blooming 3 separately with the face face opposition side that is coated with tackifier on, the deflector roll 24 of carrying usefulness suitably is set.As stated, only under the situation of the another side applying blooming of light polarizing film 1, in first blooming 2 shown in Fig. 1 and second blooming 3, only use a side (for example only first blooming 2) and get final product.Straight arrows among the figure is meant the flow direction of film, and curve arrow is meant the sense of rotation of roller.

About light polarizing film 1; In not shown light polarizing film manufacturing process; Most cases be to the polyvinyl alcohol resin film through uniaxial tension, utilize the dichromatism pigment dyeing, and dyeing after the boric acid crosslinking Treatment make after, under the state that promptly is wound into reel under this state, supply with, certainly; After the light polarizing film that also can in light polarizing film manufacturing process, make temporarily is wound into reel, go out by drawing power traction again.On the other hand, first blooming 2 and second blooming 3 are drawn by the not shown reel utilization machine of drawing respectively.Each film with identical linear velocity for example the linear velocity about 10～50m/ minute carry with the identical mode of flow direction.First blooming 2 and second blooming, 3 streamwise limits for example apply the tension force limit about 50～1000N/m and draw.

In addition; Utilize first coating machine 10 and second coating machine 12 to implement aforesaid working procedure of coating (A); Utilize first, second spectral interference formula

film thickness gauge

14,15 and the 3rd, the 4th spectral interference formula

film thickness gauge

16,17 to implement aforesaid mensuration operation (B); Utilize to fit with

niproll

20,21 enforcement aforesaid bonding processs (C),, implement aforesaid control operation (D) thus through the

coating machine

10,12 of turning back of the mensuration result with spectral interference formula

film thickness gauge

14,15,16,17.The gravure roll 11,13 that coating

machine

10,12 is had for having the roller of groove, is pre-charged with tackifier in this groove, under this state, make blooming 2,3 rotations, and tackifier is transferred on the blooming 2,3.Through adjusting this rotational speed, can adjust the quantity delivered of the tackifier on the blooming 2,3, and then the adjustment coating thickness.In this case, the adjusting mechanism of the rotational speed of gravure roll, especially gravure roll becomes mechanism's (control part of coating thickness control gear or coating thickness) of the coating thickness of

control coating machine

10,12.

Describe based on the block diagram of Fig. 2 relation these each operations.At first, in setting (0),, in the scope of 0.5～5 μ m, set setting thickness Y in advance for the thickness of the tackifier of coating in above-mentioned working procedure of coating (A).From aforesaid reason, set thickness Y and be preferably set to 1～4 μ m, more preferably be set at 1.5～3.5 μ m.In addition, as preceding half operation of measuring operation (B), utilize spectral interference formula film thickness gauge 14,16 to measure the thickness of blooming 2,3 in advance after, the initial stage condition of the mechanism of the coating thickness of control coating machine 10,12 is set, make working procedure of coating (A) running.Then; As the later half operation of measuring operation (B); Utilize spectral interference formula film thickness gauge 15,17; The gross thickness of tackifier to after blooming and the coating is measured, and obtains the thickness of the tackifier after the coating by the absolute value of the difference of the measured value of the measured value of preceding half operation and later half operation, exports as measuring thickness X.No matter how this measures thickness X, in bonding process (C), the blooming 2,3 that has been coated with tackifier is fitted on the two sides of light polarizing film 1 with tackifier coated face separately.On the other hand, in control operation (D), this mensuration thickness X and above-mentioned setting thickness Y are compared.In addition; For example when the absolute value of measuring thickness X and the difference of setting thickness Y with respect to set thickness Y become more than the defined threshold, for example 5% when above; Make the coating thickness control gear running of coating machine 10,12; The mode that diminishes according to both absolute value of difference, preferably according to the absolute value of measuring thickness X and the difference of setting thickness Y with respect to setting the threshold value of thickness Y, for example controlling coating thickness less than 5% mode less than regulation.At this, the so-called absolute value of measuring thickness X and the difference of setting thickness Y is meant more than 5% to satisfy following formula (I) with respect to setting thickness Y, in Fig. 2, determines whether that according to whether satisfying this formula the condition that changes control gear representes.Need to prove that the mensuration thickness X in this embodiment is not limited to the above-mentioned method in Fig. 2 explanation with the control methods of setting thickness Y.That is, measure thickness X and both can not be based on the contrast of measuring thickness X and setting the difference of thickness Y, also can not be based on the contrast of absolute value with the contrast of setting thickness Y.For example; Can according to measure below the threshold value whether thickness X and the difference of setting thickness Y be regulation with respect to the ratio of setting thickness Y or more than the threshold value for regulation, for example-5% below or+5% with on compare, can also according to measure thickness X with respect to the ratio of setting thickness Y whether be below the threshold value of regulation or more than the threshold value of regulation, for example below 95% or 105% with on compare.Above-mentioned threshold value is not limited to 5% (perhaps-5%, 95% etc.), can be lower value, for example 1% or 3%, also can be higher threshold value, for example 7% or 10%.In addition, the threshold value of upside can adopt different value (for example-3% or more than 7%) with the threshold value of downside.

[several 1]

\frac{| X - Y | \times 100}{Y} &GreaterEqual; 5 - - - (I)

Below, working procedure of coating (A), mensuration operation (B), bonding process (C) and the control operation (D) that constitutes method of the present invention is elaborated.In addition, under the situation of using the active energy ray curable tackifier, more than having passed through, after each operation, implement curing process (E), therefore also this operation is described.

(A) working procedure of coating

In the working procedure of coating (A), at the coating binder on the binding face of light polarizing film 1 of the blooming 2,3 of preceding half operation of having passed through mensuration operation (B) (measuring the operation of the thickness of blooming self).At the coating machine of this use, as long as have the mechanism that coating thickness is controlled, just not special the qualification uses the mode of the gravure roll of explaining with reference to Fig. 1 11,13 representative.In using the coating machine of gravure roll, the reverse rollers coating machine (reverse roll coater) that direct gravure coater (direct gravure coater), closed knife type coater (chamber doctor coater), hectograph intaglio plate coating machine are for example arranged, used the rhynchostome coating machine of gravure roll, constitutes with many rollers etc.In addition, can utilize have scraper cylindraceous and to coating part supply with the tackifier limit with scraper scrape the limit coating the point type coating machine, use slit mould etc. and directly supply with the mould of tackifier and be coated with machine, make intercepting basin scrapes the coating of remaining liquid limit with knife-edge various coating machines such as cutter formula coating machine.Wherein, when considering the degree of freedom etc. of thin film cladding, trace, even if in the coating machine that uses gravure roll; Preferred direct gravure coater, closed knife type coater, hectograph intaglio plate coating machine etc.; In addition, except gravure roll, the mould of also preferred use slit die is coated with machine.Because tackifier corresponding with the wide cutization of polarization plates easily, that supply with liquid is difficult to emit foul smell, so further preferred closed knife type coater.

At this; Closed knife type coater is to instigate closed scraper and the gravure roll butt that has absorbed liquid coating (tackifier); Coating in the closed scraper (tackifier) is transferred in the groove of gravure roll, and it is transferred to the coating machine as the mode on the blooming that is applied thing 2,3.Be designed to small-sized closed knife type coater and also be called as little closed knife type coater.

Under the situation of using the gravure roll coating binder, the thickness of adhesive layer can be according to the adjustment recently with respect to linear velocity of the speed of gravure roll.Be made as 10～50m/ minute through linear velocity blooming 2,3; Make gravure roll carry out retrograde rotation with respect to the throughput direction of blooming 2,3; And the rotation round speed of gravure roll was made as 10～500m/ minute, the coating thickness that can adjust tackifier thus is 0.5～5 μ m.The coating thickness of this moment is owing to also receive the voidage influence on gravure roll surface, preferred gravure roll of selecting to have the voidage on the surface that is suitable for setting thickness Y in advance.Need to prove, make the mode of gravure roll retrograde rotation be also referred to as reverse gravure with respect to the throughput direction of blooming 2,3.

(B) measure operation

In preceding half operation of the mensuration operation (B) of the preceding enforcement of working procedure of coating (A); Utilize the spectral interference method to measure the thickness of blooming self; Utilize the spectral interference method to measure the gross thickness of the tackifier after blooming and the coating in the later half operation of the mensuration operation of implementing in working procedure of coating (A) back (B), obtain the thickness of the tackifier after the coating by the absolute value of the difference of the measured value of the measured value of preceding half operation and later half operation.Said here spectral interference method is to be used to obtain the mode of thickness from the reflected light on the surface of determinand with from the catoptrical interference at the back side.

That is, during to the blooming before the coating binder self irradiates light, produce from the reflected light on the surface of film with from the reflected light at the back side of film; If these 2 kinds of reflected light phase places are identical; Then strengthen each other, if phase place on the contrary then weaken each other, so become interference light.The contained wavelength region may (the for example wavelength region may of 810～830nm) of scope surpassing 800nm makes this interference light carry out beam split, and the beam split waveform patterns that obtains is carried out Fourier transform, obtains the thickness of optics thus.Under the situation as necessity, refractive index that can be through it being considered blooming (for example, the thickness of the optics through blooming is divided by the refractive index of blooming) is obtained the thickness of this blooming at the thickness of blooming.On the other hand; During from the adhesive layer side irradiates light of the blooming that has been coated with tackifier; Still produce from the reflected light on adhesive layer surface with from the reflected light at the back side of film, produce and above-mentioned same interference light, with it and above-mentionedly carry out beam split equally by them; And carry out Fourier transform, obtain the thickness of optics thus.Under oneself the situation of total thickness of adhesive layer and blooming as necessity; Must consider the mean refractive index of the duplexer of adhesive layer and blooming; But the thickness of adhesive layer is unknown, so its volume is also unknown, therefore is difficult to the mean refractive index of using this moment.

Like this; Say the refractive index that not only must consider tackifier by reason, also must consider the refractive index of blooming, but among the present invention; The thickness of obtaining tackifier owing to the film thickness difference before and after the coating of tackifier gets final product, so in fact can ignore the refractive index of blooming.Promptly; In preceding half operation of measuring operation (B); Through to the blooming irradiates light before the coating binder; If will to the thickness of the optics that obtains thus considered tackifier refractive index, in fact this blooming can be considered the thickness (the apparent thickness of the blooming before the coating binder) that replaces to the state behind the tackifier and exports; In the later half operation of measuring operation (B); From the adhesive layer side irradiates light of the blooming that has been coated with tackifier, if will to the thickness of the optics that obtains thus considered tackifier refractive index, in fact this blooming can be considered the thickness (the apparent thickness of the blooming behind the coating binder) that replaces to the state (being loaded with the state of tackifier on it originally) behind the tackifier and exports, and then obtains the thickness of tackifier of absolute value as both differences.Need to prove, both difference for negative situation under, need not necessarily use absolute value, can with both simple poor as tackifier thickness and obtain.In addition, after the difference of the optical thickness that the thickness of tackifier also can be through the blooming before obtaining coating binder and the optical thickness of the blooming behind the coating binder, obtain divided by the refractive index of tackifier with this difference.

According to the film thickness gauge that is principle with aforesaid spectral interference method; Can be under situation the about thickness of tackifier after the coating not being exerted an influence; Poor as the gross thickness of the thickness of the blooming before the working procedure of coating self and blooming behind the working procedure of coating and tackifier obtained the thickness of tackifier with good precision.In addition, obtain the method for this embodiment of the thickness of tackifier by the film thickness difference before and after the coating of tackifier, have following advantage:, can obtain the thickness of tackifier no matter have or not refringence between blooming and the tackifier.

With the film thickness gauge of aforesaid spectral interference method, can from commercially available article, select the film thickness gauge that is fit to as principle.Commercially available spectral interference formula film thickness gauge majority is based on above-mentioned principle, in film thickness gauge, carries out sequence of operations automatically, and the measured value in measured value repeatedly or stipulated time is average, as the instrument of the form of measured value output.Thickness about operable spectral interference formula film thickness gauge in this embodiment can be measured from following the restriction of employed minute optical wavelength, is generally more than the 10 μ m.As be used for light-struck light source, be preferably the to have the wavelength region may contained light source of light of (the for example wavelength region may of 810～830nm), can use SLD (Super Luminescent Diode) etc. above the scope of 800nm.In this embodiment, preferably being chosen in off-line state, to make the resolution characteristic of the thickness under the state that film leaves standstill be the film thickness gauge of the level of 1～10nm.

In addition; Viewpoint from the stability of thickness measurement value; The spectral interference formula film thickness gauge that uses among the present invention preferably 0.00001～1 second, especially can measure film thickness gauge once at 0.00001～0.5 second measuring interval, more preferably obtain moving average and the film thickness gauge that can export for 10～100000 continuous measured value by the data that obtain.For example, surpass 100000 points and measuring interval surpasses under 0.5 second the situation at the number of times of moving average, the deviation of measured value and actual (real) thickness can become big sometimes.From same reason, further preferred use is carried out mensuration once at 0.0001～0.2 second measuring interval, by the film thickness gauge of the data that obtain for 10～70000 continuous measured value output moving average.

In order to improve the Determination of thickness precision of tackifier; Measure the blooming self before the working procedure of coating thickness spectral interference formula film thickness gauge be provided with the position, with the position that is provided with of the spectral interference formula film thickness gauge of the gross thickness of measuring blooming and tackifier behind the working procedure of coating, preferably the Width about blooming is consistent.In addition, from same reason,, preferably make thickness measurement point consistent about the length direction (throughput direction) of blooming.And then from same reason, the preferred at interval length direction along blooming that is provided with of 2 spectral interference formula film thickness gauges is made as in the 10m, more preferably is made as 1～5m.

In with the film thickness gauge of aforesaid spectral interference method as principle, the only polarized light that sends by light source (for example SLD etc.), and also the degree of this polarized light is different because of each film thickness gauge sometimes, and perhaps this polarized light is multiple mixing ripple.Under these circumstances, especially in the face more than blooming has 300nm under the situation of phase difference value,, also can produce the difference of the above measured value of 0.5 μ m even if measure identical blooming.In this embodiment; As previously mentioned; In preceding half operation of measuring operation (B), measure the thickness of blooming self; When in the later half operation of measuring operation (B), measuring the gross thickness of blooming and the tackifier that is coated with above that; Consistent through making from these direction of vibration direction of vibration of the strongest polarized light (under the situation of the mixing ripple of a plurality of polarized lights for) at the polarized light that the light source of the film thickness gauge that preceding half operation and later half operation are used sends, can suppress error at measurment to a certain extent sometimes based on aforesaid polarized light.In addition, especially in the face more than blooming has 300nm under the situation of phase difference value, the near infrared polarization optical filter is set between spectral interference formula film thickness gauge and blooming preferably.Under the situation that the near infrared polarization optical filter is set, the axis of homology of this near infrared polarization optical filter or absorption axes become the mode of the angle of 45 degree to be configured with the length direction (being throughput direction, usually as fast axle or slow axis) with respect to blooming usually.If the direction of vibration of the polarized light that sends with the light source from the film thickness gauge direction of vibration of the strongest polarized light (under the situation of the mixing ripple of a plurality of polarized lights for) is configured with the overlapping mode of the axis of homology of near infrared polarization optical filter, then can improve the light quantity of the reflection interference light that is used for determining film thickness.

(C) bonding process

Through above working procedure of coating (A) and after measuring operation (B), be implemented in the overlapping light polarizing film 1 of each tackifier coated face of blooming 2,3 and the bonding process (C) of pressurization.The pressurization of this operation can be used known mechanism, but from can the limit carrying the viewpoint of limit pressurization continuously, the preferred mode of utilizing a pair of

niproll

20,21 to carry out clamping as shown in Figure 1.In this case, on light polarizing film 1 opportunity of overlapping blooming 2,3, with utilize a pair of

niproll

20,21 preferably identical with respect to the opportunity that 1 pair of blooming of light

polarizing film

2,3 pressurizes, even if different, the difference on both opportunitys is also preferably short more good more.The combination of a pair of

niproll

20,21 can be any of middle lattice such as metallic roll/metallic roll, metallic roll/rubber rollers, rubber rollers/rubber rollers.Pressure during pressurization preferably is made as about 150～500N/cm in line pressure under the situation of utilizing a pair of

niproll

20,21 clampings.

(D) control operation

In this embodiment, the result based on the mensuration operation (B) of above explanation is provided with the control operation (D) that the coating thickness of the tackifier in the working procedure of coating (A) is controlled.Promptly; Thickness at the tackifier of working procedure of coating (A) coating; According to the surface tension of the temperature of tackifier or ambient temperature, blooming 2,3 or to its tension force that applies etc., have some variations sometimes, sometimes with deviation from the coating thickness of wanting (setting thickness Y).In order to revise the deviation of such coating thickness, be the basis to measure the coating thickness (mensuration thickness X) that utilizes the spectral interference method to measure in the operation (B), the coating thickness control gear that coating machine had is controlled.Particularly, when measuring thickness X, the coating thickness control gear is controlled, when measuring thickness X, the coating thickness control gear is controlled with the mode that increases coating thickness greater than setting thickness Y with the mode that reduces coating thickness greater than setting thickness Y.

For example, be coated with machine, then when measuring thickness X, make ability drop, when measuring thickness X, improve the ability of liquor charging on the contrary, can control coating thickness thus to mould less than setting thickness Y from liquor chargings such as pumps to mould greater than setting thickness Y if coating machine is a mould.In addition, if coating machine is for using the closed knife type coater of gravure roll, then when measuring thickness X greater than setting thickness Y; The rotating speed of reverse gravure is increased, improve rotation round speed; The transfer printing amount of tackifier is reduced, when measuring thickness X, the rotating speed of reverse gravure is reduced, reduce rotation round speed on the contrary less than setting thickness Y; Increase the transfer printing amount of tackifier, thus the may command coating thickness.The control degree of film thickness monitoring can be experimentally at random set according to its often envirment factor, the viscosity of tackifier, the surface configuration of blooming etc.Based on measuring thickness X and setting the control of coating thickness control gear of the reality of thickness Y, can use a computer and carry out, also can manually carry out.

(E) curing process

Such as stated, behind applying blooming on the light

polarizing film

12,3, if tackifier is an active energy ray curable, then through making the curing process (E) of this adhesive solidification make polarization plates 4 through the irradiation of active energy beam.In the instance shown in Fig. 1, this curing process (E) is implemented from the active energy beam of active energy beam irradiation unit 18 through the duplexer behind applying blooming on the light

polarizing film

12,3 is shone.In this operation,, cross blooming 2 and shine in order to make active energy ray curable adhesive solidification energy needed.Particularly,, use electron ray or ultraviolet ray, select according to the curing reaction mechanism of tackifier as active energy beam.About electron beam irradiation device, from not revealing the necessity of covering in the mode of outside with the electron ray that produces, device size, weight increase.On the other hand, because ultraviolet lamp has more small-sized structure, so can preferably use the curing that utilizes the ultraviolet ray irradiation to carry out.

In the example shown in Fig. 1; The duplexer irradiation active energy beam that light polarizing film 1 and blooming 2,3 are fitted by tackifier; In the applying of irradiation unit 18 front and back with

niproll

20,21 and coiling front nip rollers 22, between 23, under the state that duplexer is applied tension force, carry out.Be not limited thereto, preference as shown in TOHKEMY 2009-134190 communique is open, form circular-arc convex surface being supported on along throughput direction, be typically under the state of outer peripheral face of roller the irradiation active energy beam.Particularly when the irradiation through active energy beam produces heat and might produce bad influence to goods; Preferably as duplexer that the latter is shown in by under the state of the outer peripheral face of roller supporting to shining active energy beam it on; In this case, the roller of supporting duplexer preferably can be in the range regulation temperature about 10～60 ℃.In addition, can 1 active energy beam irradiation unit only be set, also can be provided with more than 2, shine by a plurality of light sources and not only effectively improve the accumulation light quantity, and be effective along the flow direction of duplexer at irradiated site.

Make at irradiation ultraviolet radiation under the situation of adhesive solidification; Employed ultraviolet light source is not special to be limited, but can use the for example low pressure mercury lamp that below wavelength 400nm, has luminescence distribution, medium pressure mercury lamp, high-pressure sodium lamp, ultrahigh pressure mercury lamp, chemical lamp, black lamp, microwave-excitation mercury lamp, metal halide lamp etc.Use is with under the situation of epoxy compound as the tackifier of active energy ray-curable composition; When considering absorbing wavelength that common polymerization initiator shows, preferred high-pressure sodium lamp with the light below a large amount of 400nm or the metal halide lamp of using is as ultraviolet light source.

When as the tackifier irradiation ultraviolet radiation of curable composition it being solidified with epoxy compound, the linear velocity of duplexer is not special to be limited, but almost keeps to former state the linear velocity in working procedure of coating (A), the bonding process (C) usually.In addition, preferred limit applies the tension force of 100～1000N/m to the length direction (throughput direction) of duplexer, and the limit makes counts 100～1500mJ/cm to the exposure of the effective wavelength region may of activate of polymerization initiator with accumulation light quantity (to the gross energy of duplexer irradiation) ²To the accumulation light quantity of tackifier when very few; The curing reaction of active energy ray curable tackifier is not enough; Be difficult to embody sufficient adhesion strength, on the other hand, when this accumulation light quantity is excessive; The heat that produces through by the heat of radiation of light source and tackifier polymerization the time might cause the xanthochromia of active energy ray curable tackifier or the deterioration of light polarizing film.

In addition, when wanting to reach needed accumulation light quantity, through the heat release meeting film is reached and surpass 150 ℃ high temperature, in this case, might cause the deterioration of light polarizing film etc. with 1 time ultraviolet ray irradiation.Take place for fear of such state of affairs, the throughput direction along film as discussed previously is provided with a plurality of ultraviolet lamps, is divided into that repeatedly to shine be effective.

As target, preferred sometimes as follows: the exposure from the ultraviolet lamp at 1 place is made as 600mJ/cm to accumulate quantometer ²Below, finally obtain 100 above-mentioned～1500mJ/cm ²The accumulation light quantity.

The polarization plates of as above, making, in the scope of setting, the deviation of intermembranous bonding strength that constitutes polarization plates is little with the THICKNESS CONTROL of tackifier, and the air blister defects in the adhesive layer etc. are also few, and are also excellent as the quality stability of goods.

[embodiment]

Embodiment and comparative example below are shown, further the present invention are specified, but the present invention does not receive the qualification of these instances.Need to prove; The experiment that below illustrates is used to confirm that the effect of being brought by the present invention carries out; For example, the clamping light polarizing film, with the thickness of the tackifier of the opposition side coating of the tackifier of measuring thickness; Do not produce the mode of defective with it, carry out note setting the thicker situation of optimum value that adopts than practical operation.

Fig. 3 is the side view that schematically illustrates the configuration of the device that uses in following embodiment and the comparative example.Configuration shown in Figure 3 is compared with Fig. 1 of previous explanation, only following 2 differences, and the position beyond the difference has the symbol identical with Fig. 1, so the explanation with reference to Fig. 1 is hoped in the detailed description at these positions.

Fig. 3 is with respect to the difference of Fig. 1:

During (1) to the irradiation active energy beam of the duplexer behind fit respectively on the two sides of light polarizing film 1 first blooming 2 and second blooming 3 (ultraviolet ray); The limit makes second blooming, 3 sides and the outer peripheral face driving fit of irradiation with take up roll 26 of this duplexer; The limit is from this duplexer of clamping and be configured in first blooming, the 2 side irradiation ultraviolet radiations of 18 pairs of duplexers of active energy beam (ultraviolet ray) irradiation unit of the opposition side of take up roll 26, and

(2) owing to only 1 formula (2) spectral interference formula film thickness gauge arranged, so measure the thickness at the tackifier of first blooming, 2 coatings is measured with spectral interference formula

film thickness gauge

14,15, coat the thickness mensuration not of the tackifier of second blooming 3.

In addition, as spectral interference formula

film thickness gauge

14,15, used the spectral interference formula film thickness gauge " SI-F80 " of the Keyence of Co., Ltd. system.This spectral interference formula film thickness gauge is the device of thickness being measured with the spectral interference method of previous explanation, and light source is SLD, and its beam split wavelength region may is 810～830nm, and resolution characteristic is 1nm.In addition; Measure the thickness of determinand at each predefined measuring interval,, other film thickness value of said determination is carried out moving average for each same predefined mensuration number of times; And the average film thickness of inciting somebody to action is therebetween exported; And in the measured value of predefined number of times, automatically get rid of the data that are judged to be exceptional value, and output average film thickness.

[embodiment 1]

(0) material that uses in the experiment

In this example; As first blooming 2; The biaxial orienting property phase retardation film " KC4FR-1 " (obtaining) of used thickness 40 μ m, width 1330mm and the triacetyl cellulose system supplied with from roller from Konica Minolta Opto Co., Ltd.; As second blooming 3, used thickness 80 μ m, width are 1330mm and the triacetylcellulose film " KC8UX2MW " (obtaining refractive index 1.48 from Konica Minolta Opto Co., Ltd.) still supplied with from roller.Be used for the tackifier of the bonding light polarizing film 1 and first blooming 2 and be used for bonding light polarizing film 1 and second blooming 3 tackifier, all contain epoxy compound and Photoepolymerizationinitiater initiater and not solvent-laden in fact epoxy is the light-cured type tackifier.

(A) working procedure of coating

To on polyvinyl alcohol (PVA), be adsorbed with iodine and iodine carried out the light polarizing film 1 of the thickness 25 μ m of orientation, as the above-mentioned phase retardation film of first blooming 2, and, supply with 15m/ minute linear velocity and the identical mode of flow direction respectively as the above-mentioned triacetylcellulose film of second blooming 3.On the face that fits to light polarizing film 1 of the phase retardation film 2 of preceding half operation of the mensuration operation of after having passed through, having stated (B) (measuring the operation of the thickness of blooming itself), using first coating machine 10 (" little closed scraper " of machinery Co., Ltd. of Fuji system) that possesses gravure roll 11 to be coated with above-mentioned epoxy is the light-cured type tackifier.In addition, on the face that fits to light polarizing film 1 of triacetylcellulose film 3, using second coating machine 12 (being similarly " little closed scraper " of machinery Co., Ltd. of Fuji system) the above-mentioned epoxy of coating that possesses gravure roll 13 is the light-cured type tackifier.

Make the gravure roll 11,13 that is arranged at coating

machine

10,12 carry out retrograde rotation with respect to the direction of transfer of film.In addition, in second coating machine 12 of triacetylcellulose film 3 sides, set in the following manner: the rotation round speed of it gravure roll that possesses 13 is 15m/ minute, on film with the thickness coating binder of about 4.5 μ m.It is following film: undetermined does not carry out its film thickness monitoring, so the thickness coating binder of defective almost not occur with the thickness of the tackifier of second coating machine, 12 coatings yet.On the other hand, in phase retardation film 2 sides, the rotation round speed initial setting of the gravure roll 11 that first coating machine 10 is possessed is 21m/ minute, with the thickness coating binder of about 2.6 μ m.

(B) measure operation

Upstream side at first coating machine 10 disposes the first spectral interference formula film thickness gauge 14, disposes the second spectral interference formula film thickness gauge 15 in the downstream of first coating machine 10, along the 1.67m that is spaced apart of the film flow direction of two coating machines.In addition, utilize the thickness of the first spectral interference formula film thickness gauge 14, set for ({ (2 with 0.0002 second measuring space phase retardation film 2 ²) ²} ²) ²=2 ¹⁶Each of=65536 times continuous measured value (about 13.1 seconds) exported moving average (preceding half operation) successively.In addition; After having passed through above-mentioned working procedure of coating; The second spectral interference formula film thickness gauge 15 through configuration; Still with the gross thickness of 0.0002 second measuring space phase retardation film 2 and tackifier, each that set continuous measured value (about 13.1 seconds) to 65536 times for exported moving average (later half operation 1) successively from the adhesive applicating face side of phase retardation film 2.Therefore; After the beginning; After through about 13.1 seconds of the measured value that obtaining 65536 times; Per 0.0002 second moving average from the thickness of the first spectral interference formula film thickness gauge, 14 phase difference output films 2; From the moving average of the second spectral interference formula film thickness gauge, 15 phase difference output films 2 with the gross thickness of tackifier, but being respectively to extract this value in per 1 second, (is that (poor (B-A) that be the measured value=B) of the gross thickness of phase retardation film 2 and tackifier sets (later half operation 2) as the mode that the mensuration thickness X is write down successively for Determination of thickness value=A) and the latter's the value of phase retardation film 2 with the former value in this moment.Then; The control operation of stating after being provided with (D), limit are controlled the limit to above-mentioned mensuration thickness X and are carried out about 150 minutes operation, and (the data number is about 150 minutes * 60/minute to obtain the mensuration thickness X that obtains therebetween; About 9000) mean value and standard deviation, the result is shown in table 1.

(C) bonding process

To phase retardation film 2 and the triacetylcellulose film 3 that has been coated with tackifier, separately tackifier coated face and light polarizing film 1 is overlapping, and utilizing fits carries out clamping with

niproll

20,21 with these line pressures with 240N/cm.Passed through the duplexer of phase retardation film 2/ light polarizing film 1/ triacetylcellulose film 3 behind the

niproll

20,21; With these triacetylcellulose film 3 sides be set at 20 ℃ irradiation with the mode of the outer peripheral face driving fit of take up roll 26; Apply the tension force of 600N/m along long axis direction; With with fit before identical linear velocity 15m/ minute, carry from the ultraviolet limit of ultraviolet lamp 18 its phase retardation film 2 sides irradiation on the limit.Ultraviolet lamp 18 is the GSYuasa of a Co., Ltd. system, from 2 they UV-lamps that possess " EHAN1700NAL high-pressure sodium lamp " irradiation ultraviolet radiation.About ultraviolet accumulation light quantity, 2 lamps add up to 330mJ/cm ²Adhesive layer is solidified, and the single-sided lamination that is produced on light polarizing film 1 has phase retardation film 2, is fitted with the polarization plates 4 of triacetylcellulose film 3 at another side, and is wound up on the take up roll 30.

(D) control operation

In the control operation; The mensuration thickness X that above-mentioned mensuration operation is obtained is compared under the situation about differing more than 5% with setting thickness Y=2.6 μ m; Be | under the situation of X-Y| >=0.13 μ m; The rotation round speed of the gravure roll 11 that the limit will be provided with at first coating machine 10 increases and decreases speed with 0.5m/ minute unit, and the limit is controlled to the coating thickness of tackifier near setting thickness Y.

[comparative example 1]

Among the embodiment 1; Control operation (D) is not set; That is, change, the rotational speed of the gravure roll 11 that first coating machine 10 possessed is changed even if measure the mensuration thickness X that obtains in the operation (B); Make duplexer in the case, then carry out ultraviolet ray irradiation equally and made polarization plates.The mean value and the standard deviation of the mensuration thickness X in the time of will carrying out about 150 minutes operation are shown in table 1.

[comparative example 2]

Among the embodiment 1; Attempt not being provided with the first spectral interference formula film thickness gauge 14; And the beam split wavelength region may that Otsuka Electronics Co., Ltd.'s system is set as the second spectral interference formula film thickness gauge 15 is the reflection beam splitting film thickness gauge " FE-2900CCD " of 230～800nm, in measuring operation (B), utilizes this reflection beam splitting film thickness gauge directly to measure the coating thickness of tackifier; In addition, likewise made polarization plates with embodiment 1.But because the refractive index (1.48) of the phase retardation film of the triacetyl cellulose system of using as first blooming 2 is approaching with the refractive index (1.49) of tackifier, so the thickness of tackifier can't be measured, so the coating thickness of tackifier is uncontrollable.

[embodiment 2]

Among the embodiment 1; The biaxial orienting property phase retardation film " KC4FR-1 " that replaces triacetyl cellulose system; And the biaxial stretch-formed pet film of used thickness 38 μ m, width 1330mm (is obtained by Mitsubishi Plastics Inc; Phase difference value 1000nm in the face) as first blooming 2, in addition, likewise made polarization plates with embodiment 1.The mean value and the standard deviation of the mensuration thickness X in the time of will carrying out operation in about 150 minutes are shown in table 1.

[embodiment 3]

Among the embodiment 2; For spectral interference formula

film thickness gauge

14 and 15, respectively between spectral interference formula film thickness gauge and biaxial stretch-formed pet film, the flow direction that becomes with respect to biaxial stretch-formed pet film with the absorption axes of polarized light wave filter is provided with polarized light wave filter (Edmund Optics corporate system to the mode of the direction of right rotation 45 degree; Near infrared polarization optical filter from the acquisition of Edmund Optics Japan Co., Ltd.; The function wavelength region may is 750～800nm), in addition, likewise make duplexer with embodiment 2; Then carry out the ultraviolet ray irradiation equally, made polarization plates.The mean value and the standard deviation of the mensuration thickness X in the time of will carrying out operation in about 150 minutes are shown in table 1.

[comparative example 3]

Among the embodiment 3; Control operation (D) is not set, that is, changes even if measure the mensuration thickness X that obtains in the operation (B); The rotational speed of the gravure roll 11 that first coating machine 10 possessed is changed; Make duplexer in the case, then carry out the ultraviolet ray irradiation equally, made polarization plates.The mean value and the standard deviation of the mensuration thickness X in the time of will carrying out operation in about 150 minutes are shown in table 1.

[the flaw evaluation test of polarization plates]

In the foregoing description and the comparative example; In the polarization plates that obtains with the 1330mm width; The 1250mm width segments of central authorities of two ends respectively being removed the 40mm width segments is as effective width, for the face that in this effective width, spreads all over flow direction 3300mm length (1.25m * 3.3m ≈ 4m ²), with visualization mark is carried out at the position of bright spot, and then the mark position is used the magnifier observation of 100 times of enlargement ratios and confirmed whether be bubble, if bubble is then obtained its size with following main points.That is, if observed bubble is approximate ellipsoidal (comprising circle), then be the size of bubble with the longest diameter, if bubble is a wire, then be the size of bubble with its line length.In addition, the counting size is the above bubble quantity and bubble of 100 μ m, is every 1m in this quantity ²Be less than under 0.3 the situation 4m that promptly observes ²Being to count " OK " under 0 or 1 's the situation in the area, is every 1m in this quantity ²Be the 4m that under the situation more than 0.3, promptly observes ²Be to count " NG " under the situation more than 2 in the area, the result is compiled in the table 1 with main variables.In the table, " TAC " that be positioned at the blooming hurdle is meant triacetyl cellulose, and " PET " is meant polyethylene terephthalate.Need to prove; About bubble with the size more than the observed 100 μ m of magnifier; The mode that gets into this bubble is cut into the size of 40mm * 40mm with film, and observes with microscope, and the result can confirm all at the adhesive layer that is clipped between the light polarizing film 1 and first blooming 2.

[table 1]

Annotate) OK: the above bubble quantity and bubble of big or small 100 μ m is every 1m ²Be less than 0.3.

NG: the above bubble quantity and bubble of big or small 100 μ m is every 1m ²Be more than 0.3.

As shown in table 1, for the comparative example 1 and 3 that control operation (D) is not set, the mensuration thickness change of tackifier; Accompany with it, observe air blister defect on the polarization plates that obtains, relative therewith; For the mensuration thickness X that control operation (D) and tackifier are set with set thickness Y and compare and differ 5% and make when above for the embodiment 1 and 2 of coating thickness change; Can know with setting thickness Y and compare that measure thickness and probably be suppressed to 5% with interior change, air blister defect is also few.And then, for the embodiment 3 that specific polarized light wave filter is set, further, can also suppress its change near setting thickness between spectral interference formula film thickness gauge and blooming 2.On the other hand; Of comparative example 2; When using the beam split wavelength region may, under the situation of the difference of the refractive index of refractive index that does not almost have tackifier and blooming, can't measure the coating thickness of tackifier as the reflection beam splitting film thickness gauge of the scope of the ratio broad below the 800nm.

Claims

1. the manufacturing approach of a polarization plates, it has following operation:

Operation (A): use the coating machine of the control part of coating thickness, the said tackifier of coating on the blooming of thermoplastic resin system with tackifier;

Operation (B): utilize the beam split wavelength region may is set in above the spectral interference method in the scope of 800nm; Optical thickness to the blooming behind the optical thickness that is coated with the blooming before the said tackifier and the said tackifier of coating is measured, and tries to achieve the thickness of the said tackifier after the coating based on the difference of the optical thickness of the optical thickness of the blooming before the said coating binder and the blooming behind the said coating binder;

Operation (C): on the tackifier coated face of the said blooming that passes through said mensuration; The light polarizing film of overlapping polyvinyl alcohol resin system; With respect to said light polarizing film said blooming is pressurizeed, said light polarizing film and said blooming are fitted by said tackifier; And

(D) be based on the thickness X that the quilt of setting thickness Y and the said tackifier of the said tackifier of setting in the scope of 0.5～5 μ m is obtained, the operation that said control part is controlled.

2. the method for claim 1, wherein

The absolute value of the difference of the thickness X of obtaining when the quilt of said tackifier and the setting thickness Y of said tackifier is setting when above with respect to the ratio of the setting thickness Y of said tackifier, and said control part is controlled.

3. the absolute value of the difference of the thickness X of the method for claim 1, wherein obtaining when the quilt of said tackifier and the setting thickness Y of said tackifier is 5% when above with respect to the ratio of the setting thickness Y of said tackifier, and said control part is controlled.